#include "stdafx.h"

/*
 * -- SuperLU routine (version 2.0) --
 * Lawrence Berkeley National Lab, Univ. of California Berkeley,
 * and Xerox Palo Alto Research Center.
 * September 10, 2007
 *
 */
/*
 * File name:	dlaqgs.c
 * History:     Modified from LAPACK routine DLAQGE
 */
#include <math.h>
#include "hnum_pdsp_defs.h"

#ifdef small
#undef small
#endif


namespace harlinn
{
    namespace numerics
    {
        namespace SuperLU
        {
            namespace Double
            {
                void dlaqgs(SuperMatrix *A, double *r, double *c,  double rowcnd, double colcnd, double amax, equed_t *equed)
                {
                /*
                    Purpose   
                    =======   

                    dlaqgs() equilibrates a general sparse M by N matrix A using the row and   
                    scaling factors in the vectors R and C.   

                    See supermatrix.h for the definition of 'SuperMatrix' structure.

                    Arguments   
                    =========   

                    A       (input/output) SuperMatrix*
                            On exit, the equilibrated matrix.  See EQUED for the form of 
                            the equilibrated matrix. The type of A can be:
	                    Stype = SLU_NC; Dtype = SLU_D; Mtype = SLU_GE.
	    
                    R       (input) double*, dimension (A->nrow)
                            The row scale factors for A.
	    
                    C       (input) double*, dimension (A->ncol)
                            The column scale factors for A.
	    
                    ROWCND  (input) double
                            Ratio of the smallest R(i) to the largest R(i).
	    
                    COLCND  (input) double
                            Ratio of the smallest C(i) to the largest C(i).
	    
                    AMAX    (input) double
                            Absolute value of largest matrix entry.
	    
                    EQUED   (output) equed_t*
                            Specifies the form of equilibration that was done.   
                            = NOEQUIL: No equilibration
                            = ROW:  Row equilibration, i.e., A has been premultiplied by
                                    diag(R).   
                            = COL:  Column equilibration, i.e., A has been postmultiplied
                                    by diag(C).   
                            = BOTH: Both row and column equilibration, i.e., A has been
                                    replaced by diag(R) * A * diag(C).   

                    Internal Parameters   
                    ===================   

                    THRESH is a threshold value used to decide if row or column scaling   
                    should be done based on the ratio of the row or column scaling   
                    factors.  If ROWCND < THRESH, row scaling is done, and if   
                    COLCND < THRESH, column scaling is done.   

                    LARGE and SMALL are threshold values used to decide if row scaling   
                    should be done based on the absolute size of the largest matrix   
                    element.  If AMAX > LARGE or AMAX < SMALL, row scaling is done.   

                    ===================================================================== 
                */

                #define THRESH    (0.1)
    
                    /* Local variables */
                    NCformat *Astore;
                    double   *Aval;
                    int i, j, irow;
                    double large, small, cj;


                    /* Quick return if possible */
                    if (A->nrow <= 0 || A->ncol <= 0) {
	                *equed = NOEQUIL;
	                return;
                    }

                    Astore = (NCformat*)A->Store;
                    Aval = (double*)Astore->nzval;
    
                    /* Initialize LARGE and SMALL. */
                    small = dlamch_("Safe minimum") / dlamch_("Precision");
                    large = 1. / small;

                    if (rowcnd >= THRESH && amax >= small && amax <= large) {
	                if (colcnd >= THRESH)
	                    *equed = NOEQUIL;
	                else {
	                    /* Column scaling */
	                    for (j = 0; j < A->ncol; ++j) {
		                cj = c[j];
		                for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
		                    Aval[i] *= cj;
                                }
	                    }
	                    *equed = COL;
	                }
                    } else if (colcnd >= THRESH) {
	                /* Row scaling, no column scaling */
	                for (j = 0; j < A->ncol; ++j)
	                    for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
		                irow = Astore->rowind[i];
		                Aval[i] *= r[irow];
	                    }
	                *equed = ROW;
                    } else {
	                /* Row and column scaling */
	                for (j = 0; j < A->ncol; ++j) {
	                    cj = c[j];
	                    for (i = Astore->colptr[j]; i < Astore->colptr[j+1]; ++i) {
		                irow = Astore->rowind[i];
		                Aval[i] *= cj * r[irow];
	                    }
	                }
	                *equed = BOTH;
                    }

                    return;

                } /* dlaqgs */

            };
        };
    };
};